Muffler silencer

ABSTRACT

A silencer for a muffler canister is designed to be insertable in the canister in order to reduce exhaust noise levels while providing rattle-and vibration-free operation. The device includes a series of flexible prongs mounted on the outer surface of the silencer that enable the silencer to securely fit within the canister.

BACKGROUND OF THE INVENTION

[0001] This invention relates to devices for reducing noise emitted from internal combustion engines, generally called silencers, which may be adapted to be inserted within vehicular mufflers in such a manner as to reduce exhaust noise while providing rattle and vibration free operation. These devices are useful in aftermarket automotive exhausts particularly those systems which may fail to comply with government regulations without the silencer.

[0002] Over the past ten years, aftermarket performance mufflers and exhaust systems have become popular with automotive enthusiasts all over the world. During this time sales of such systems have increased dramatically and so have the noise levels of the automobiles using these aftermarket exhaust systems. The trend to upgrade to aftermarket systems usually stems from an enthusiast's desire to increase the performance, appearance and exhaust tone of his vehicle. Such enthusiasts usually replace the original equipment manufacturer (OEM) exhaust systems on their vehicles with aftermarket systems. The OEM systems are usually relatively quiet and tend to comply with all state and local noise level requirements.

[0003] The aftermarket exhaust systems differ from their OEM counterparts in that the exhaust tubing is usually of a larger diameter and the mufflers used within the system usually flow exhaust gases more efficiently. The resultant freer flow of exhaust gases through an aftermarket system tends to increase the vehicle's performance by reducing engine back pressure. In some cases the aftermarket components may also be lighter due to material choice or system design. Additionally, the tone of the vehicle's exhaust is usually lowered, resulting in a more powerful sounding engine.

[0004] While the performance, looks and sound of one's vehicle may be improved by replacing an OEM exhaust system with an aftermarket system, one drawback to the aftermarket system may be an unacceptable increase in exhaust noise levels. Because the aftermarket exhaust frequently uses larger, freer flowing components than an OEM system the exhaust noise is usually less muffled than it would be in the case of the OEM system. Consequently, exhaust noise levels from aftermarket exhaust are usually higher than OEM systems and in some cases much higher than OEM systems. In response to excessive noise levels produced by aftermarket exhaust systems, many state and local governments have enacted regulations imposing fines for exceeding decibel limits. To avoid facing fines, enthusiasts need a way to reduce the noise levels of their aftermarket systems. Apart from the questionable legality of aftermarket systems, some enthusiasts also tire of the excessive noise levels and seek a device for lowering the noise without significantly hindering the other beneficial aspects of aftermarket systems.

[0005] A relatively low cost and quick solution to limit excessive exhaust noise levels of an aftermarket exhaust system without detrimentally affecting performance is to install a silencer within the exhaust system's muffler. A popular aftermarket exhaust system includes a muffler canister which is generally cylindrical in shape and includes a generally cylindrical inner surface. For this particular muffler canister, a silencer with a generally cylindrical shape is configured to be insertible into the canister. The silencer usually includes a baffle to reduce exhaust noise to an acceptable level without substantially reducing exhaust flow rates. Silencers are conventionally secured in the canister with either a fastener such as a nut and bolt or a weld connection at the rear of the canister.

[0006] While such conventional silencers usually lower exhaust noise levels to reasonable levels without significantly impacting exhaust flow, the weld connection or the nut and bolt used to hold the silencer within the canister may fail to completely secure the silencer within the canister. Because the silencer is usually inserted from the rear of the muffler canister, the only component of the silencer accessible once inserted is the rearmost portion. As mentioned above it is this rearmost section that is usually either welded or secured with a nut and bolt to the muffler canister. While the connection prevents the silencer from moving along the longitudinal axis with respect to the canister, the connection is not adequate to prevent the silencer from axial movement within the canister. As the engine is operated the unsecured inner end of the silencer tends to vibrate and rattle within the canister. The vibrations and rattling may cause the weld or nut and bolt connection between the silencer and the canister to loosen and thereafter the silencer may dislodge or blow out of the canister. Additionally, the rattling and vibration may become a constant source of irritation for the vehicle's driver and passengers.

[0007] What has been needed and heretofore unavailable is a silencer that reduces engine exhaust noise levels while securably fitting within a muffler canister such that the silencer is substantially rattle- and vibration-free while the engine is being operated. The present invention satisfies this need.

SUMMARY OF THE INVENTION

[0008] The present invention is directed to providing a device which usefully reduces exhaust noise levels emitted from an internal combustion engine while providing rattle and vibration-free operation. More particularly, the present invention is directed to an exhaust silencer insertable into a muffler which, in addition to reducing exhaust noise levels, incorporates a series of flexible prongs with spring-like properties about its outer surface to secureably retain the silencer within the muffler. This secure retainment prevents the silencer from rattling and vibrating within the muffler while the engine is being operated.

[0009] The invention contemplated herein is directed to the silencer per se but for purposes of illustration it is beneficial to briefly describe one type of muffler to be used with the invention. The particular muffler contemplated to be used with one embodiment of the invention is popular with sport compact car enthusiasts. The muffler is configured in a canister-type manner and positioned at the rear of an automobile. The inside of the canister includes a generally cylindrical inner surface into which the silencer of the present invention is insertable. The canister has an inlet orifice which is coupled to an exhaust pipe extending from the automobile's engine and an outlet orifice coupled to a tip exiting the rear of the automobile. Frequently the outlet orifice is significantly larger than the inlet orifice for both visual appeal and noise enhancement.

[0010] The silencer may have a shorter length than the muffler canister and is insertable into the muffler canister through the outlet orifice. The silencer includes a first tubular member, a second relatively larger diameter tubular member and a substantially conical member connecting the two tubular members. The first tubular member supports a series of three flexibly mounted, or flexible prongs on its outer surface and includes an inner end which fits within and is spaced from, the inner surface of the canister. The second tubular member includes an outer end which conforms to the outlet orifice of the canister. The fitment of the outer end of the silencer within the outlet orifice of the canister aligns the silencer to the canister. The flexible prongs exert pressure on the inner surface of the canister to help to prevent the silencer from rattling or vibrating within the canister in addition to inhibiting longitudinal as well as axial movement of the silencer with respect to the canister, as is described in more detail below.

[0011] Mounted on the outer surface of the first tubular member, the flexible prongs are radially offset from and longitudinally aligned along the silencer's longitudinal axis with an inner end which is securely attached to the first tubular member and an outer end which extends radially and longitudinally outward. In their free state, the outer ends of the prongs circumscribe a diameter larger than the first tubular member and larger than the inner diameter of the canister. When the silencer is inserted into the canister, the prongs are radially compressed by the smaller inner diameter of the inner surface of the inner surface of the canister. The radial compression forces the free ends of the prongs to circumscribe a smaller second diameter approximately equal to the inner diameter of the canister. The prong compression operates to securely retain the silencer within the canister. This secure fitment minimizes potential vibration and rattling of the silencer within the canister and inhibits axial and longitudinal movement of the silencer with respect to the canister.

[0012] In one embodiment, the components of the silencer including the first tubular member, the series of prongs extending therefrom, the second tubular member and the conical member connecting the two tubular members may be formed from mild steel. The tubular members in particular can be made from readily available mild steel tubing such as that used for automotive exhaust systems. In this embodiment the components can be welded together in a conventional manner in the interest of minimizing costs and speeding assembly time. The welds should generally be complete around the circumference of each mating surface as an exhaust leak may inhibit the functionality of the silencer. The welds connecting the prongs to the first tubular member should also be sufficient to support the prongs in their compressed state after the silencer is inserted into the muffler canister.

[0013] The silencer is insertable into the muffler canister through the canister's outlet orifice. The silencer may be pushed into the canister up until the silencer's outer end is within the outlet orifice of the canister. Both components are configured with similar diameters so that the fit between the outer end of the silencer and the outlet orifice of the canister maintains the silencer and the canister in a substantially radially aligned manner along the longitudinal axis. Upon insertion of the silencer into the muffler, the prongs radially compress to circumscribe a diameter smaller than their free (unflexed) diameter and approximately equal to the inner diameter of the canister. This tight fit ensures that the silencer will be stabley and securably retained within the canister while the vehicle is in use. Because of the flexible, spring-like nature of the prongs, the secure fit will ensure rattle- and vibration-free operation as long as the prongs retain their spring-like properties. In one embodiment, the outer end of the silencer is welded to the outlet orifice of the canister to prevent the silencer from moving with respect to the canister along the longitudinal axis. In the case that this weld fails, the prongs may assist in retaining the silencer within the canister.

[0014] It is to be recognized that the silencer of the present invention can be configured in different forms and can be constructed from different materials and in different manners from those described above. For example the silencer may include one tubular member with a series of prongs attached to its outer surface. The silencer may also be formed from aluminized steel, titanium and stainless steel rather than mild steel. Additionally, the components of the silencer may be press fit, bolted, or bonded together rather than welded. Furthermore the silencer may be configured in different manners for insertion into other types of mufflers including non-canister type and those for other types of internal combustion engines. Such a configuration may include ovalized components in order to adapt to the different style of muffler.

[0015] Other features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a perspective view of the silencer of the present invention.

[0017]FIG. 2 is a plan view of the silencer.

[0018]FIG. 3 is an end view of the silencer, illustrated in relative position to the inner wall of the muffler canister shown in broken lines.

[0019]FIG. 4 is a plan view of the silencer within a muffler canister.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Exhaust silencers may generally be used to lower the exhaust noise levels of an internal combustion engine. The present invention is directed to a silencer which, in addition to lowering exhaust noise levels, provides rattle- and vibration-free operation. One embodiment of the silencer of the present invention is directed to a silencer for use in connection with an automotive exhaust system, more particularly for use in connection with an automotive aftermarket canister-type muffler.

[0021] A preferred embodiment of the silencer 10 of the present invention is depicted in FIGS. 1-4. As illustrated in FIG. 1, the silencer includes a first tubular member 12, a series of flexible prongs 14 connected to the first tubular member, a second tubular member 16 with a diameter relatively larger than that of the first tubular member and a conical member 17 connecting the two tubular members. This exact configuration is for use in connection with a canister muffler 42 which is illustrated in FIG. 4. Other configurations of silencers for use in connection with other types of muffler are contemplated by the invention. For example, the silencer may be configured with a single tubular member or with more than two tubular members but in all cases the silencer should include at least one flexible prong to stably mount the silencer within a muffler.

[0022] The preferred embodiment of the silencer is directed for use in connection with a cylindrical canister muffler partly because of the immense popularity of this type of canister muffler in the automotive aftermarket. In this embodiment, the first and second tubular members 12,16 are made from mild steel cylindrical tubing. The tubing may be readily available mild steel tubing suitable for use in connection with exhaust systems. In this embodiment the diameter of the first tubular member 12 is approximately 43 mm and the diameter of the second relatively shorter tubular member is approximately 98 mm. The diameter of the outer surface of the conical member 16 which is also constructed from mild steel and which connects the two members varies from about 43 mm to about 98 mm. The silencer 10 is about 250 mm in total length with the first tubular member 12 approximately 200 mm long, the conical member about 35 mm long and the second tubular member about 15 mm long. It is also contemplated by the invention that the components of the silencer may be formed from other materials including aluminized steel, titanium and different grades of stainless steel depending on design requirements.

[0023] As illustrated in FIG. 2, a total of three prongs 14 make up the series of prongs, each with radially inner ends 26 and radially outer ends 28 extending from the outer surface 20 of the first tubular member 12. The prongs 14 are connected to the outer surface through a series of weld connections 22. The weld connections secure the inner ends 26 of the prongs 14 to the first tubular member 12 while permitting the outer ends 28 to freely extend radially outwardly from the tubular member. Intermediate the inner ends 26 and outer ends 28 of prongs 14, intermediate planar surfaces 29 are preferably provided, with surfaces 29 which provide maximum abutment with the inner surface of the muffler canister 42 (see FIG. 4). The overall shape of the prongs 14 may be described as having an undulating shape in profile. While a weld connection 22 is shown in this embodiment, it is contemplated by the invention that the prongs 14 may also be formed integral to the tubing or bonded to the tubing with an adhesive.

[0024] The prongs 14 are about 100 mm long and extend about 20 mm radially outward from the first tubular member 12 in their free, or unflexed, state. They are formed from conventionally available metal which is flexible to enable the prongs 14 to radially compress, but which also has spring-like properties. The spring-like properties enable the prongs 14 to maintain resistance to compression after the silencer 10 is inserted into the canister 42 (FIG. 4).

[0025] The first tubular member 12 includes an inner end 24 which is suitable for insertion into the inlet orifice 41 (FIG. 4) of the muffler canister 42 (also shown in FIG. 4). The first tubular member also includes an outer end 27 which is connected to the conical member 17 through a weld connection 30. As illustrated in broken lines the conical member 17 has an inner collar 31 which fits within the first tubular member to align the two together and provide further support. The conical member couples the second tubular member 16 through another weld connection 32. The second tubular member 16 has an outer end 34 which is sized to fit within the outlet orifice 41 of the muffler canister 42. Together, all of the components make the silencer 10 approximately equal in length to the canister. The particular method of connecting the first tubular member and second tubular member to the conical member can also include press-fitting and bonding through an adhesive.

[0026] The three flexible prongs 14 are illustrated in FIG. 3 in their free state. As illustrated, the prongs 14 may have an undulating shape which may help the prongs to be easily compressible and readily conformable to the inner surface 44 of the canister 42 (FIG. 4) and readily conformable to other similar canisters with different inside diameters. In their free state, the outer ends 28 of the prongs 14 circumscribe a diameter D1 (FIG. 3) which is larger than diameter D2 (FIG. 4) OF the canister's inner cylindrical surface. The prongs are spaced equidistant from each other at approximately 120 degrees around the circumference of the first tubular member 12 to ensure that when the silencer 10 is inserted inTO the canister, equal pressure is distributed by the prongs to the silencer. The equal pressure ensures that the silencer remains centered within the canister. This centering may help expedite exhaust gases through the silencer by maintaining the position of the silencer within the exhaust gas's natural trajectory. The use of more or less prongs is also contemplated by the invention. In some cases, one prong may suffice to securely retain the silencer within the canister while in other cases more than three prongs may be incorporated into the present invention.

[0027] When the silencer 10 is inserted into the canister 42, the prongs 14 are radially compressed by the smaller inner diameter D2 of the canister. The radial compression forces the free ends of the prongs 14 to circumscribe a smaller second diameter approximately equal to the inner diameter D2 of the canister. This compression operates to securely retain the silencer within the canister. The secure fitment minimizes potential vibration and rattling of the silencer within the canister and inhibits axial and longitudinal movement of the silencer with respect to the canister. The degree of compression may be varied depending on the size of D1 and D2. In some cases, D1 may be much larger than D2 to ensure adequate securement of the silencer within a muffler.

[0028] The silencer 10 is shown inserted in the muffler canister 42 in FIG. 4. The prongs 14 compress radially to conform to the inner cylindrical surface 44 of the canister 42. The second tubular member 16 fits within the outlet orifice 41 of the canister 42. In this embodiment the canister 42 has an inner diameter of about 102 mm, slightly larger than the outer diameter of the second tubular member at about 98 mm. A weld joining the second tubular member to the outlet orifice is applied after the silencer is inserted into the canister in order to secure the two parts together. Other method of securing the silencer against longitudinal movement with respect to the canister can include bonding with an adhesive or using a fastener such as a nut and bolt.

[0029] While the invention has been illustrated and described herein in terms of its use in connection with an automotive muffler canister, it will be apparent to those skilled in the art that the silencer can be used in connection with other internal combustion engine exhaust systems. Further, particular sizes and dimensions, materials used, connection types and the like have been described herein and are provided as examples only. Other modifications and improvements may be made without departing from the scope of the invention. 

What is claimed:
 1. A silencer for a muffler canister, comprising: an elongate body with an outer end and an inner end; and a plurality of flexible prongs extending radially outwardly from the outer surface of the body; wherein the diameter circumscribed by the flexible prongs in their free state is relatively larger than the inner diameter of the muffler canister so as to create a secure fit between the silencer and the canister.
 2. The silencer of claim 1, wherein the inner end of the elongate body and the outer end are sized to fit within an inlet orifice and an outlet orifice of the muffler canister, respectively.
 3. The silencer of claim 2, wherein the outer end is welded to the outlet orifice.
 4. The silencer of claim 2, wherein the outer end is bolted to the outlet orifice.
 5. The silencer of claim 3, wherein the silencer comprises three flexible prongs.
 6. The silencer of claim 5, wherein the flexible prongs are coupled to the elongate body by a weld connection.
 7. The silencer of claim 5, wherein the flexible prongs are formed integral with the elongate body.
 8. The silencer of claim 6, wherein the flexible prongs have an undulating shape.
 9. The silencer of claim 8, wherein the flexible prongs have inner and outer ends, the inner ends coupled to the elongate body.
 10. The silencer of claim 9, wherein the flexible prongs have a length of less than half the length of the elongate body.
 11. The silencer of claim 10, wherein the flexible prongs have a spring-like flexibility to help minimize rattling of the silencer within the canister.
 12. The silencer of claim 11, wherein the inner end of the elongate body has a first diameter and the outer end has a relatively larger second diameter.
 13. The silencer of claim 12, wherein the elongate body is formed from a metal.
 14. The silencer of claim 13, wherein the flexible prongs are formed from a metal.
 15. The silencer of claim 14, wherein the elongate body includes an inner section, a center section and an outer section, wherein the inner section is substantially cylindrical, the center section is substantially conical and the outer section is substantially cylindrical.
 16. A silencer for a muffler canister, comprising: an elongate body configured to be insertable in a canister, the body comprising a inner end with a first diameter and a outer end with a second, relatively larger diameter, wherein the outer end is welded to the canister; and three bendable prongs circumscribing a first diameter and welded to the outer surface of the silencer and in contact with an inner surface of the canister having relatively smaller second diameter to minimize vibration and rattling of the silencer within the canister.
 17. A silencer for a muffler canister, comprising: an elongate body; and a means for securing the elongate body within a canister.
 18. The silencer of claim 14, wherein each flexible prong includes an intermediate planar surface which contacts the inner surface of the muffler canister.
 19. the silencer of claim 5, wherein the flexible prongs are coupled to the elongate body by a flexible connection.
 20. The silencer of claim 15, wherein the inner section is press-fit to the center section. 